GB-patent GB2406121B “A method and apparatus for high speed data dumping and communication for a down hole tool” describes multiple internal SPI busses for allowing rapid dumping of data via a tool interface to a PC when the tool is on the surface. It comprises a toolstring with several tools such as a source fire control board, data acquisition boards and memory boards, all connected to two or more SPI busses which allow for dumping data at high speed to an ESPI device being connected directly while on the surface to a PC for fast dumping of data. While downhole and operating it communicates via an APX controller processor and a tool modem via a logging tool modem connected to a wireline for telemetry to and from the surface.
This GB2406121B thus describes an internal high speed bus in the entire tool. The EPSI module is for increasing the dumping rate from the tool to a surface computer when the tool is out of the well. The purpose of the doubling of the SPI lines is to increase the combined speed of the tool databus so as for feeding the ESPI module in order to utilize a full Ethernet capacity when the tool is at the surface.
Advantages of the present invention relative to the above GB patent are presented under a separate section below.